1. Field of the Invention
The present invention relates to a photoconductor unit and to an image-forming apparatus having the photoconductor unit.
2. Description of the Related Art
An electrophotographic image-forming apparatus which has a photoconductor drum and a charger for uniformly charging the surface of the photoconductor drum is conventionally known. In this connection, there are known various image-forming apparatus of this type in which the flow of air around the charger is regulated during image-forming operation for forming good images, as disclosed in, for example, Japanese Patent Application Laid-Open (kokai) Nos. 2006-98509, 2004-138853, 2004-279846, and 2004-301957.
In the image-forming apparatus of this type, a white streak may appear on a formed image along the main scanning direction when image formation is performed after long-hour suspension (e.g., after suspension lasting from evening to next morning). The width of the white streak as measured along the paper transport direction is substantially equal to the width of a space between the charger and a drum-cleaning member as measured along the sub-scanning direction (along the direction of rotation of the photoconductor drum). The drum-cleaning member is configured and disposed so as to clean a circumferential surface of the photoconductor drum before the circumferential surface is uniformly charged by the charger.
The white streak prominently appears when the environment during suspension is of high temperature and high humidity (e.g., 32° C. and 80%). Also, the longer the suspension time, more prominently the white streak appears.
Taken together, the above facts imply that the white streak is induced by a phenomenon such that substances (an external additive of toner, etc.) filming the circumferential surface of the suspended photoconductor drum absorbs moisture. Conceivably, moisture absorption on the circumferential surface of the photoconductor drum results from absorption of moisture from air which is stagnant in the space between the charger and the drum-cleaning member.